Geophysical Journal | 2000 volume 22 Ή5

Model and experimental studies of the process of the oil and gas deposit identification by dynamic signs of active seismic monitoring

© A.E. Gai, S.V. Mostovoi, V.S. Mostovoi, A.E. Osadchuk, 2000

The approach to detection of an oil-gas deposit is under consideration. For this purpose the dynamic characteristic of seismic record is used. These records are the researched media response to a sounding signal series. They are the regulated nonexplosive broadband seismic signals. A mathematical model of experiment is offered. The field tests were conducted on an oil-gas province (in near by Pryluki town). These results of registration, processing and analysis were obtained by using a computeraided seismic monitoring system. The frequency range of the system was from 0,1 to 30 Hz. A concept of seismic fields monitoring is offered. Its using enables us to identify an oil-gas deposit, in a selected space of characteristics and to evaluate the parameters that describe it. Two aspects of this problem are considered. The first aspect is an optimal choice of the sounding signal characteristics and optimal evaluation of the medium response to this signal according to the background noise. The second phase is a mapping medium response into space informative characteristics for deposit identification. This space of the characteristics should be selected so that distance in this space between different objects of identification is a maximum value. The choice procedure of characteristic space and the algorithms of pattern recognition are based on heuristics. The model of sounding impulse flow is represented by a s tochastic non-stationary binomial flow (Bernoulli process). The power of fluctuating impulses is weak and is commensurable with a microseismic background noise. The microseismic background noise is simulated by a stochastic stationary process with zero expectation and finite variance. The space of indications is selected from wavelet damping characters. The wavelet is the medium response. The medium is transformed into this character space as a trajectory of time function. The identification and evaluation of deposit parameters is carried out if the trajectory passes through the fixed areas into this space. The experimentation was in a region with an oil-gas deposit, and in a region without deposit.

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